---
source: https://iinventedlight.com/library/notes/gamma-ray-bursts.md
title: "Gamma-ray bursts and the Swift observatory"
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
source_license: "US government work, public domain; restated in our own words"
attribution: "Summary by iinventedlight (AI-assisted). Sources: NASA, Imagine the Universe!, US government work, public domain; NASA, Swift: About Swift, US government work, public domain."
author: "iinventedlight (synthesis of cited sources); text drafted with AI assistance"
date: 2026-11-04
status: published
checked_on: 2026-11-04
as_of: 2026-11-04
confidence: medium
untested: "No observation or experiment was done; only the fetched government pages were read."
category: coverage-gaps
topic_area: "space science: stars"
tags: ['nasa', 'gamma-ray-bursts', 'swift', 'black-holes']
sources:
  - id: S1
    title: "Imagine the Universe!"
    publisher: NASA
    url: https://imagine.gsfc.nasa.gov/science/objects/bursts1.html
    accessed: 2026-11-04
    license: "US government work, public domain"
  - id: S2
    title: "Swift: About Swift"
    publisher: NASA
    url: https://swift.gsfc.nasa.gov/about_swift/
    accessed: 2026-11-04
    license: "US government work, public domain"
---
# Gamma-ray bursts and the Swift observatory

**Answer:** Gamma-ray bursts (GRBs) are short-lived bursts of gamma-ray light, the most energetic form of light. Lasting anywhere from a few milliseconds to several minutes, they shine hundreds of times brighter than a typical supernova. Evidence from satellites like Swift and Fermi indicates that the energy behind a burst comes from the collapse of matter into a black hole.

## Discovery

GRBs were discovered serendipitously in the late 1960s by U.S. military satellites on the lookout for Soviet nuclear testing. The satellites carried gamma ray detectors since a nuclear explosion produces gamma rays. They didn't find any violations of the nuclear treaty, but they did discover bright bursts of gamma rays from beyond the solar system.

## Two classes

When astronomers looked at the number of bursts versus how long they lasted, they found two classes: long-duration and short-duration. These two classes are likely created by different processes, but the end result in both cases is a brand new black hole.

## The Swift observatory

Swift is a multi-wavelength observatory dedicated to the study of gamma-ray burst science. Its three instruments observe GRBs and afterglows in the gamma-ray, X-ray, ultraviolet, and optical wavebands.

- Swift discovers approximately 100 bursts per year.
- The Burst Alert Telescope detects GRBs and accurately determines their positions on the sky.
- Swift relays a 3 arcminute position estimate to the ground within 20 seconds of the initial detection.
- In less than approximately 90 seconds the spacecraft autonomously repoints itself to observe the afterglow with its X-ray and UV/optical telescopes.

## Claims
- id: C1
  claim: Gamma-ray bursts are short-lived bursts of gamma-ray light.
  source: S1
  evidence: "Gamma-ray bursts (GRBs) are short-lived bursts of gamma-ray light"
- id: C2
  claim: GRBs fall into long-duration and short-duration classes.
  source: S1
  evidence: "long-duration and short-duration."
- id: C3
  claim: Swift discovers approximately 100 bursts per year.
  source: S2
  evidence: "Swift discovers approximately 100 bursts per year."

## Sources
- [S1] Imagine the Universe!. NASA. https://imagine.gsfc.nasa.gov/science/objects/bursts1.html . License: US government work, public domain. Accessed 2026-11-04.
- [S2] Swift: About Swift. NASA. https://swift.gsfc.nasa.gov/about_swift/ . License: US government work, public domain. Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).